@vflorio94 this error can happen frequently, it happens when the url is available, but the board doesn't accept connections. Or when the board is starting, it might take a few seconds to be able to connect to it. You don't have another connection to the board, right? (And I assume you have tried hard resetting, disconnecting power then trying again)

Hi @vflorio94, are you connected to the module via its WiFi? Alternatively, you could use serial (with the USB cable) to connect to it, you can get the list of serial ports by clicking on "All commands->List Serial Ports" and it'll copy it to your clipboard. Next, you can paste it in pymakr.conf.